This study questions whether, when talking about graphical stimuli (and in particular, advertisements), attention is above the surface of consciousness that leads to a voluntary perception of the existing stimuli; or if attention is an involuntary process so that we perceive a selection of the stimuli our brain has previously chosen. Previous research of Cognitive Psychology based on advertising attention and perception documents that our cognitive response directly depends on the level of attention focused on the existing stimuli. To understand this question, we need to determine the parameters governing our level of attention.